Acetaminophen is widely used for treatment of pain and/or fever in the elderly. This dual action is sometimes contraindicated. In many instances, pain needs to be controlled without masking the symptomatic fever (e.g., fever due to infection during the postoperative period). Acetaminophen can also cause hepatotoxicity, particularly after ingestion of large doses or chronic use of smaller doses (especially in the elderly or when liver function is affected), which can lead to death. Therefore, there is a need for new more selective compounds with greater pharmacological anti-pain potency and devoid of hepatotoxic or antipyretic effect. SCP-1 is the lead compound from St Charles Pharmaceutical's series of new proprietary derivatives of acetaminophen. SCP-1 has high analgesic activity but is free from antipyretic activity and hepatotoxicity In STTR Phase I, we explored the biological properties of SCP-1 in young and old animals. SCP-1 was effective and much less toxic than acetaminophen in young and old animals, and had an attractive pharmacokinetic profile. In STTR Phase II, we will further test and develop this drug in Phase II for treating pain in the elderly where acetaminophen is contraindicated. The analgesic properties of SCP-1 will be evaluated using two pain models: the Freund's Adjuvant inflammation assay and the formalin pain assay. We also will perform mechanism-of-action and pharmacokinetic studies using radiolabeled [14C] SCP-1.